Frequent

QUESTIONS

Here is a collection of the most frequently asked questions (FAQs) about the scientific and technical area of the MEF.

1. What are fossils?

2. What should I do if I find a fossil?

3. How are fossils formed?

4. How are dinosaur eggs preserved without being broken?

5. How are the ages of fossils determined?

6. How do they study the environments and climate changes that have occurred in the past?

7. If the fossils were buried in sediment and lava, why are they now exposed or found close to the surface?

8. Why did the dinosaurs die off?

1. What are fossils?

Fossils are remains of organisms preserved in the earth’s crust. But indications of their existence and activities are also considered fossils.

In other words, fossils aren’t only the familiar bones and tree trunks. Palaeontologists also search for various and diverse clues and signs such as eggs, nests, footprints and even excrement ( the latter are called coprolites). These signs of the acvtividad or presence of an organism are referred to as “trace fossils.”

Only a small fraction of all of the plants and animals that lived in the past are preserved in the form of fossils. They are true evidence of change, signs of bygone geological epochs that tell thier own story of of the environment in which they lived.

Researchers are interested in other aspects related to fossils, beyond descibing only their characteristics. These include:

- understanding their anatomical function.

- understanding the evolutionary changes that a type of organism undergoes.

- Determining their age from the geological record

- Locating the species in its evolutionary tree (phylogeny), amongst others.

For this reason, they rely on original specimens which are then compared to others (sometimes descriptions in the scientific literature). They also examine the remains in light of other evidence available, such as traces of their activity preserved in rocks, enviromental changes recorded on the geological layers, etc.

A researcher could spend days studying the material, or they may dedicate years to it. Other researchers may even want to study or reexamine the fossil in light of new discoveries.

2. What should I do if I find a fossil?

Firstly one should not try to remove it and/or take it as a souvenir or for a private collection, as it is punishable by National Law No. 25, 743 “ Protection of Archeological abnd Palaeontological Hertitage” and by Provincial Law No. 3599 “ Governing archeological, anthropol;gical and palaeontological ruins and sites.”

This is the legal framework. But what is the spirit of the regulations? Their removal could cause damage and even loss of fragments crucial to the understanding of this record of prehistoric life that could be completely unique.

On the other hand, extraction of a fossil without considering the setting in which it’s found could result in the irrecuperable loss of fundamental information which could help to understand still more about these living things from the past. For example, it is important to know what type of sediments the fossils are found in, in what place they were found and the geological era to which they belong.

Likewise, fossils ought to be available to future generations and hence should be kept in an appropriate place for thier long term preservation, such as in museum collections.

The proper way to proceed upon encountering a fossil is to communicate with the appropriate provincial authority responsible for the application and enforcement of the National and Provincial Laws. In the case of the Province of Chubut, this is Provincial Culture Secretariat.

Due to the great territorial expanse of Chubut, this Secretariat works together with other institutions including the provincial police and municipalities. Hence, another way to register the finding is through the closest police department or municipality, who will immediately contact the Secretariat of Culture to decide on the next steps for follow-up .

Yet another alternative is to communicate with a renowned scientific institution, such as a museum or university, who in collaboration the the Secretariat of Culture will determiine the appropriate steps to be taken.

In summary: What to do upon finding a fossil?

> Don’t dig up the fossil or remove it from its place.

> Communicate the finding with the Secretariat of Culture, or if that isn’t possible, a museum or other recognised scientific institution, or the closest police commission.

3. How are fossils formed?

The study of the changes that occur in an organism from its death until its discovery is the topic of Taphonomy, one of the specializations of Palaeontology. Fossilzation isn’t a common phenomenon, and the deciphering of fossils either singly or found in associations is not simple.

In this long process, fossils undergo important physical and biological changes. These could include fracturing, markings or variations in the dispositions or arrangements of the bones. When the fossil is recovered, these signs can help to unravel part of the “post mortem” story of the organism.

4. How are Dinosaur eggs preserved without thier being broken?

The dinsoaurs , which ruled the Earth for more than 65 million years, cared for their eggs much like many modern birds: building a nest to protect and shelter them. It seems that they preferred the soil near rivers, and that’s where they layed them without burying them. The nests ,which have been found in various places, have contained up to 11 eggs, often arranged in circles.

How does an egg manage to last for millions of years without being broken?

In the first place, the vast majority don´t survive: if the egg doesn’t hatch, it can be destroyed in many ways. But occasionally, given the right circumstances conducive to its preservation, it can survive until the present.

The long process stars with the overflow of a river, carrying sand and other sediments which cover the egg without breaking it. Then there exist two possible mechanisms of fossilization:

Some eggs have had only thier shells petrified. In others, the invasion of minerals has reached the interior as well. In this case, the filling of the egg by opal (amorphous silica) would have occurred through the tiny pores in the shell. Of course at that point there were no vestiges of organic components in the egg.

Afterwords, tectonic forces and intense and continuous erosion of the sediments uncovered the bedrock carrying the eggs. This allowed their discovery by palaeontologists.